/*                                                                                           
 * This file is part of CLAPACK, the f2c'ed version of LAPACK                                
 * hosted at netlib.org.                                                                     
 *                                                                                           
 * For more information, see the LAPACK User's Guide:                                        
 *                                                                                           
  @BOOK{laug,                                                                                
        AUTHOR = {Anderson, E. and Bai, Z. and Bischof, C. and                               
                  Blackford, S. and Demmel, J. and Dongarra, J. and                          
                  Du Croz, J. and Greenbaum, A. and Hammarling, S. and                       
                  McKenney, A. and Sorensen, D.},                                            
        TITLE = {{LAPACK} Users' Guide},                                                     
        EDITION = {Third},                                                                   
        PUBLISHER = {Society for Industrial and Applied Mathematics},                        
        YEAR = {1999},                                                                       
        ADDRESS = {Philadelphia, PA},                                                        
        ISBN = {0-89871-447-8 (paperback)}  }                                                
 *                                                                                           
 */ 

/*  -- translated by f2c (version 19940927).
   You must link the resulting object file with the libraries:
	-lf2c -lm   (in that order)
 */

#include "f2c.h"

doublereal dnrm2_(integer *n, doublereal *x, integer *incx)
{


    /* System generated locals */
    integer i__1, i__2;
    doublereal ret_val, d__1;

    /* Builtin functions */
    double sqrt(doublereal);

    /* Local variables */
    static doublereal norm, scale, absxi;
    static integer ix;
    static doublereal ssq;


/*  DNRM2 returns the euclidean norm of a vector via the function   
    name, so that   

       DNRM2 := sqrt( x'*x )   



    -- This version written on 25-October-1982.   
       Modified on 14-October-1993 to inline the call to DLASSQ.   
       Sven Hammarling, Nag Ltd.   


    
   Parameter adjustments   
       Function Body */
#define X(I) x[(I)-1]


    if (*n < 1 || *incx < 1) {
	norm = 0.;
    } else if (*n == 1) {
	norm = abs(X(1));
    } else {
	scale = 0.;
	ssq = 1.;
/*        The following loop is equivalent to this call to the LAPACK 
  
          auxiliary routine:   
          CALL DLASSQ( N, X, INCX, SCALE, SSQ ) */

	i__1 = (*n - 1) * *incx + 1;
	i__2 = *incx;
	for (ix = 1; *incx < 0 ? ix >= (*n-1)**incx+1 : ix <= (*n-1)**incx+1; ix += *incx) {
	    if (X(ix) != 0.) {
		absxi = (d__1 = X(ix), abs(d__1));
		if (scale < absxi) {
/* Computing 2nd power */
		    d__1 = scale / absxi;
		    ssq = ssq * (d__1 * d__1) + 1.;
		    scale = absxi;
		} else {
/* Computing 2nd power */
		    d__1 = absxi / scale;
		    ssq += d__1 * d__1;
		}
	    }
/* L10: */
	}
	norm = scale * sqrt(ssq);
    }

    ret_val = norm;
    return ret_val;

/*     End of DNRM2. */

} /* dnrm2_ */

